Printing of indicia on packaging, particularly corrugated cases and related packaging used for shipping, and increasingly display, of consumer products is well known in the art. But as more packaging becomes ‘shelf-ready’ and placed directly on a retail shelf, the demand for improved print quality has increased.
Print quality can be adversely affected by variations in line speed, vibration of the line, misalignment of print heads relative to one another, misalignment of print heads relative to the desired position on the case or package, clogging of print nozzles, etc. If the printing is out of specification, the case or package may not be suitable for display. Product may either be scrapped or re-packed, increasing manufacturing cost.
Additionally, a line may be used to print indicia on a short-term basis. For example, promotional packaging may include indicia specific to that promotion. At the same time long term indicia may remain on the same products. For example, trademarks, instructions for use and legally required indicia may be printed on an ongoing basis. But indicia related to, e.g. a holiday promotion or price adjustment may be added on a short term basis. Each of the short term and long term indicia may have separate or dedicated banks of print nozzles.
Various attempts have been made to overcome these problems. For example, diagnostic checkmarks have been printed on cases. But this attempt can be unsightly if the checkmarks are visible to the consumer. And printing a checkmark on each unit can be wasteful if the line is running properly. Even printing at a set, pre-determined frequency is wasteful if the line is running is within acceptable specifications. And a checkmark for long term indicia may be unnecessary if startup problems only occur with short term indicia. Accordingly, a better system is needed.
Related attempts include U.S. Pat. No. 7,413,276, U.S. Pat. No. 7,543,903, U.S. Pat. No. 7,831,863, U.S. Pat. No. 8,150,106, U.S. Pat. No. 8,355,639, US 2008021877, US2005207768, JP 2001239730, JP2006211665, JP2014188783, WO201411435 and commonly assigned U.S. Ser. No. 14/685,617.